According to a study recently published in the American Journal of Clinical Nutrition, older women who lose weight but do not maintain the loss might suffer some negative consequences in their overall health. The National Institute on Aging sponsored the investigation.
Investigators at Wake Forest Baptist Medical Center, demonstrated that within a year, some older women gain a considerable amount of weight back after losing it.
Barbara Nicklas, Ph.D., a gerontologist at the J. Paul Sticht Center on Aging and Rehabilitation at Wake Forest Baptist and lead researcher for the investigation, explained:
“The body composition of some of the women was worse than before their weight loss. When older women lose weight, they also lose lean mass. Most women will gain a lot of the weight back, but the majority of the weight regained is fat.”
78 postmenopausal women were analyzed in the study, one year after losing 12% of their body weight by dieting in a completely separate studey. Participants averaged 58 years of age. The team recorded their body composition, including change in body weight, fat and muscle, immediately before and after initial weight loss, and then again 6 and 12 months later. During the first year after initial weight loss no weight loss intervention occurred.
Their was to find out if the composition of body weight regained following intentional weight loss is comparable to the composition of body weight lost.
At the six-month follow-up after the study ended, 53 of 78 (68%) of women regained some weight, while 52 of 68 (76%) of women regained some weight at the 12-month follow-up. 16 women (24%) continues to lose weight after the program, while 11 women (16%) weighed more than they did at baseline at the 12-month follow-up.
75% of women who regained weight gained over 4.4 pounds at the 6-month follow-up. At 12-month follow-up this number increased to 84%. The researchers examined whether lost lean mass from intentional weight loss was recovered in women who regained more weight.
The team discovered that the fat mass in these women was rising to a higher level than was lean mass during the post-intervention period.
During the diet program, 67% of weight loss was fat while 33% was muscle. 81% of the entire weight regained during 12 months of follow up was fat, while 19% was muscle. On average, 26% of fat lost was regained by 12-months after the diet program, while only 6% of muscle lost was gained back.
“Most people will regain their weight after they lose it. Young people tend to regain weight in the proportion that they lost it. But the older women in our study did not appear to be regaining the muscle they lost during initial weight loss in the same way.”
Although researchers are unsure what the long term effects of losing muscle mass in middle age and older women are, combined with loss of bone density which is known to occur as individuals age, the loss of muscle may increase their risk of falling, as well as other things.
“There are certainly a lot of health benefits to weight loss, if you can keep the weight off. For older women who lose weight, however, it is particularly important that they keep the weight off and continue to eat protein and stay physically active so that, if the weight does come back, it will be regained as muscle instead of fat.”
Nicklas warns that study results were restricted to sedentary, abdominally obese, postmenopausal women, and the among younger populations or men the discoveries may differ. “Future studies of weight cycling are needed to determine its effects on muscle strength, quality, and function and body composition in older adults after all weight lost is regained”, she said.
The investigators explain:
“Many health complications associated with overweight and obesity are improved with weight loss. However, negative consequences (such as loss of muscle mass and bone density) are also associated with weight loss and are detrimental for older adults, which results in a reluctance to recommend international weight loss in this population. Because lean mass loss in older adults may be associated with the development of adverse health events and disability, it is important to examine whether the benefits of weight loss outweigh the risks in this population.”
Written by Grace Rattue